1.5 Humans and Pollution

Pollution is the addition of a substance or an agent to an environment through human activity, at a rate greater than that at which it can be rendered harmless by the environment, and which has an appreciable effect on the organisms in the environment.

Pollutants may be in the form of organic or inorganic substances, light, sound or thermal energy, biological agents or invasive species, and may derive from a wide range of human activities including the combustion of fossil fuels.

Pollution may be non-point or point source, persistent or biodegradable, acute or chronic.

Pollutants may be primary (active on emission) or secondary (arising from primary pollutants undergoing physical or chemical change).

Dichlorodiphenyltrichloroethane (DDT) exemplifies a conflict between the utility of a “pollutant” and its effect on the environment.